1. Field of the Invention
The present invention relates to an image display apparatus and an image display method for generating and displaying a depth image, which indicates a depth of a stereoscopic image, from a stereoscopic image for stereoscopic viewing, as well as a program for causing a computer to carry out the image display method.
2. Description of the Related Art
It has been known that stereoscopic viewing can be achieved with using parallax by generating a stereoscopic image, which allows stereoscopic viewing, from two or more images of the same subject taken from different viewpoints and stereoscopically displaying the stereoscopic image. As a specific technique for stereoscopically displaying the stereoscopic image, it has been proposed to display the two or more images on a monitor which allows stereoscopic viewing, such as a monitor of a parallax barrier system or a lenticular system. In this case, the stereoscopic display is achieved by generating a stereoscopic image by cutting the two or more images into vertical strips and alternately arranging the strips. Further, a technique to achieve the stereoscopic display with using afterimage effect has been proposed, in which display of a left image and display of aright image are alternated by switching the display at a high speed with changing the direction of light beams from the left image and the right image through the use of image separation glasses or an optical element attached on a liquid crystal display (scanning backlight system).
Further, various techniques for improving appearance of the stereoscopically displayed stereoscopic images have been proposed. For example, a technique to be used when a composite image is generated by combining a stereoscopic image obtained through photographing and a stereoscopic image generated using a CG technique has been proposed (see Japanese Unexamined Patent Publication No. 2006-211383, which is hereinafter referred to as Patent Document 1). In this technique, frequency characteristics of the stereoscopic images are adjusted to eliminate a feeling of strangeness of the composite image.
However, although the technique disclosed in Patent Document 1 allows elimination of the feeling of strangeness when the stereoscopic images are combined, a distance in the depth direction of each subject contained in the stereoscopic images cannot be checked. Therefore, the positional relationship in the depth direction between the subjects contained in the composite image may be altered from the actual positional relationship.